THE ADSORPTION OF POLYSTYRENE SULFONATE AND ETHOXYLATED NON-IONIC SURFACTANTS AT CARBON BLACK-WATER INTERFACE

The adsorption of a series of sodium polystyrene sulfonates with a narrow distribution of molecular weight and ethoxylated non-ionic surfactants ( NP-12, NP-40, NP-100 and C₁₆E₂₀ ) was investigated at carbon black-water interface. Adsorption isotherms of the Langmuir type were obtained for all the samples with negative adsorption free energies. The dependence of maximum of adsorption on molecular weight tor PSSNa was used to obtain information on the macromolecular conformation at the interface; surface geometry effects on adsorption conformation were analyzed using a simplified fractal approach. PSSNa does not adopt a flat conformation at the interface. Non-ionic surfactants ( NP-12, NP-40, NP-100 and C₁₆E₂₀ ) are adsorbed at the interface with the EO chains in a coil conformation.